Lavrov told the Russia Today television channel that recent signs that parts of Syria's chemical arsenal were being moved -- a development that alarmed Western governments -- was an effort by the government to make the weapons more secure.
"Our information is ... that the latest reports about some movement of the chemical weapons was related to steps undertaken by the government to concentrate the chemical stuff ... at two sites, to make sure it is absolutely protected," he said.
This correlated with information the Americans had, he said.
Citing European and US officials, media reports in early December said Syria's chemical weapons had been moved and could be primed for use in response to any dramatic gains by rebels fighting to topple Assad in a conflict that has killed more than 40,000 people since March 2011.
The United States warned it would take action against such an escalation, though Syria said it would never use chemical weapons against its own people.
"I don't believe Syria would use chemical weapons," Lavrov told RT.
"It would be political suicide for the government if it does."
Russia has angered the West and some Arab states by vetoing three UN Security Council resolutions meant to put pressure on Assad.
Lavrov said on Friday that neither side could win the civil war, part of an effort to row back after a deputy was quoted as saying the rebels could win and that Russia was working on plans to evacuate its citizens if necessary.
In his RT interview, Lavrov defended Russia's refusal to press Assad to quit, emphasising Moscow's opposition to military intervention.
Reiterating criticism of NATO plans to deploy Patriot missiles in Turkey - which the alliance says are meant to bolster Turkey's defences against a possible missile attack from Syria - Lavrov suggested the real goal could be to protect a radar installation that is part of a system the United States is building to protect itself against potential attacks from Iran.
Russia says the anti-missile shield will undermine its own security and the issue is a major irritant in Russian-American relations.
Asked whether the Patriot deployment was "more about Iran than Syria", Lavrov said: "Well, that's what some people say. And the configuration as it is being presented in the media really looks like it could be used against Iran."
It is unclear whether Russia does intend to evacuate its citizens from Syria. Russian news agency Interfax cited a naval source as saying last week that Russia had sent warships from the Baltic Sea to the Mediterranean in case it had to do so.
Itar-Tass and Interfax cited military sources as saying two landing craft had left a Black Sea port on Monday and would call at Russia's naval supply and maintenance facility in the Syrian port of Tartous.
However, it was not clear whether the movements were anything more than part of a regular rotation. The Defence Ministry declined to comment.
MOSCOW (Reuters) -- Russian Foreign Minister Sergei Lavrov has said he doesn't believe Syrian President Bashar Assad's government would use chemical weapons in the country's civil war, saying in remarks broadcast on Monday that to do so would be "political suicide".